Condenser discharge high frequency ignition system



Jan. 7, 1958 o. E. BowLus ET AL 2,819,428

CONDENSER DISCHARGE HIGH FREQUENCY IGNITION SYSTEM Filed July '7. 1953 5Sheets-Sheet l1 Jan. 7, 1958 o. E. BowLUs ET AL 2,819,428

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United States Patent -O i CONDENSER DISCHARGE HIGH FREQUENCY IGNITIONSYSTEM Omer E. Bowlus and Kenneth A. Graham, Detroit, Mich., assignorsto Chrysler Corporation, Highland Park, Mich., a corporation of DelawareApplication July 7, 1953, Serial No. 366,426

25 Claims. (Cl. 315-213) This invention relates to a low voltage typehigh frequency ignition system for internal combustion engines. Moreparticularly, the present invention relates to an automotive vehicleengine ignition system which includes a capacitor discharge circuitassociated with the engine ignition distributor and which is adapted toprovide a high frequency ignition spark to initiate the combustionprocess.

This invention has previously been described in copending applicationSerial No. 286,572, filed on May 7, 1952, now abandoned of which thisapplication is a continuation-in-part.

The operation voltage which is employed in the circuit of the presentinvention between the power source and the individual spark plug unitson the engine is approximately 2,000 volts. In the conventional internalcombustion engine ignition systems, the operating Voltage isapproximately 12,000 to 15,000 volts. This higher voltage is distributedthroughout the entire distributor circuit as well as at the spark plugs.

The frequency of the ignition spark in the present invention isapproximately ve megacycles, which is considerably higher than thatobtained in the conventional systems. f

An object of the present invention is to provide a condenser dischargespark ignition system for internal combustion engines having a highdischarge frequency which produces an ignition current with a steep wavefront thereby providing a rapid energy discharge at the spark plug andan instantaneous breakdown of the spark plug gap which in turn resultsin the successful firing of fouled spark plugs as well as clean plugs.

Another object of the present invention is to provide a condenserdischarge ignition system of the type which is adapted to be energizedby transformer means which in turn is operated from a source of D. C.supply and of the type in which circuit opening contacts in thetransformer primary circuit are adapted to interrupt the source of D. C.supply so that the polarity in the transformer secondary circuit isinherently always of the same sign. If the transformer secondary circuithas the same polarity throughout the operation of the system, it will bepossible to impress a negative voltage on the hot electrode (usually thecenter electrode) in the two-electrode spark plug. Since the hightemperature or hot electrode emits electrons more freely than arelatively colder body, a spark can be initiated at a relatively lowervoltage across the electrodes when the hot electrode is made negative.

Another object of the present invention is to provide a high frequencyignition system which includes at least a pair of transformer coils anda breaker circuit means for alternately interrupting the current in theprimaries of thek transformers wherein the breaker circuit meansincludes a plurality of breaker contacts, one portion of which isadapted to interrupt thev current in the transformer primaries and theother portions of which are adapted to distribute the flow of primarycurrent to lor 2,819,428 Patented J an, 7, 1958 ice from one or theother of the transformer primaries or' both in such a sequence that theother portion of the contacts is not subjected to arcing. This featuretends to preclude any appreciable amount of metal transfer between thecontacts.

According to another feature of the invention, a condenser dischargeignition system is provided in which two transformer ignition coilsthereof are adapted to be similarly wound and similarly terminaled andare identical in all respects to each other thereby reducing theproblems of assembly and of part replacement.

According to another feature of the invention, a novel condenserdischarge ignition system is provided in which the timing is controlledat the breaker points ratherv than at a spark gap provided between thedistributor rotor and the fixed contacts in the distributor cover as inthe case of conventional distributors.

Another object of the invention is to provide a capacitor dischargeinternal combustion engine ignition system which has low losses due tostray capacity associated with the wiring harness. This feature willresult from the relatively low voltage to which the circuit issubjected. The low voltages handled by the distributor circuit aretransformed into high tension voltage only after the electrical energyreaches the individual spark plug transformers. Therefore, completeshielding of the system may be accomplished without appreeiably loweringthe spark plug firing voltages and without disturbing engine performanceat critical speeds. f

Another object of the present invention is to provide a high frequencycapacitor discharge ignition system having at least two ignition coilswhich are each subjected to an energy storing phase of the operatingcycle for approximately of the total operating time. It is also anobject to arrange the energy storing phases of the operating cycles forthe two coils to cause an overlapping of each other thereby permittingadequate supplies of electrical energy to accumulate and preventing aldropping off of the spark plug tiring voltage at maximum engine speeds.The discharging phase of the operating cycle should be approximately 20%of the total cycle.

In order to realize the foregoing objectives, a spark gap element isintroduced into each of the coil circuits which serve as rectifyingmeans to prevent the overlapping phase periods of one coil frominterfering with the phase periods of the other and to prevent thedischarge of the capacitance in the circuit out of proper sequence. Suchspark gaps are as effective as the more expensive rectifier devices orsimilarly functioning electrical equipment in insulating the twoportions of an integrated distributor circuit from each other and alsoare adapted to provide a substantially instantaneous switching effectwhere required in the operating cycle. The presence of the spark gapsprevents a discharge of one portion when the other portion is tiring.

Further features, objects, and advantages will either be specificallypointed out or become apparent when for a better understanding of theinvention, reference is made to the following written description takenin conjunction with the accompanying drawings in which:

Figure 1 is a view of an assembled automotive distribf utor for thepresent ignition system;

present ignition system;

Figure shows the timing sequence of the sets of respective contacts inthe distributor;

Figures 11, 12, and 13 show oscillograph traces of characteristicvoltage curves obtained in the present ignition system;

Figure 14 is a showing of a portion of each of the curves of Figures1l-13 but to a magnified scale;

Figure 15 is an overall wiring diagram of the preferred form of thepresent ignition system;

Figures 16 and 17 are modications of the system of Figure l5;

Figure 18 is a section through the spark gap block of the system ofFigure 16; and

Figure 19 is a wiring diagram of a two coil distributor circuit havingdual breaker points.

This present application for Letters Patent is a conitnuation-in-part ofthe copending application Serial No. 286,572, filed May 7, 1952.

A preferred embodiment of the present invention is particularly shown inFigures 1 through 15 of the drawings and includes a distributor and adouble ignition coil type of ignition circuit which is suitable for useon multicylinder internal combustion engines. The distributor isgenerally designated by the numeral 10 and is particularly illustratedin Figures l, 2, 3, and 4. The distributor 10 includes a cylindricallystepped casing 12, a mounting flange 14 on the bottom portion of thecasing 12, and a shaft 16 which is rotatably mounted in the casing 12and which includes a depending end. When the distributor is used with afour-stroke cycle engine of the type presently contemplated, the shaft16 is geared to operate at one-half crankshaft speed. The presentinvention is particularly suited for use with a V-S automotive engineignition system in which the shaft 16 rotates one-eighth of a revolutionduring the time interval between the tiring of the successive cylinders.

The distributor 10 is provided with a vacuum spark advance chamber 18which is attached thereto by means of one or more screws 20. An oil cupis provided at the side of the distributor, and a detachable distributorcover 22 is secured at the top. The distributor cover 22 has anupstanding spark gap block 24 located centrally thereof and issurrounded by a plurality of ignition leads 26, each of which in turnextends to a separate cylinder of the engine. The cover 22 is detachablyheld on the distributor casing 12 by means of a pair of diametricallyopposed snap clips 28 which are adapted toy permit the removal of thecover 22.

Figures 2, 3, and 4 show the distributor with the cap 22 removed toexpose the inner parts of the distributor. The shaft 16 extends upwardlyinto the upper end portion of the distributor and carries thereon afour-lobed cam 30 and an eight-lobed cam 32, both of which are coupledto the shaft 16 in known manner.

The shaft 16 also detachably carries at its upper end a brush orcontact-typerotor 34. The rotor 34 comprises a body portion of aninsulating material such as Bakelite and is provided with a conductivemetallic bar 36 secured to the top of the body portion by means of ascrew 37. A pair of brushes 38 is secured to the outer end of the bar 36and are spring pressed upwardly, as seen in Figure 3, thereby causing asliding engagement with a set of fixed contacts 40 which are mounted inthe distributor cover. One contact 40 s electrically connected to theigniters in each of the engine cylinders by means of the leads 26. Thebar 36 also has an inner portion 42 which slidably engages a contactcentrally mounted in the distributor cover 22. The ignition coils whichare contem plated for use in the present two-coil type ignition system,are preferably similarly wound, have similarly located terminals, andhave identical electrical characteristics. For the purpose ofsimplifying the assembly of the present ignition system and for purposesof economy of manu-V facture, the two coils may be duplicates of eachother.

4 Also it has been found that the ignition coils which are used on theD. C. ignition systems currently employed by the majority of Americanautomotive manufacturers, may be readily adapted for assembly into thepresent twocoil high frequency system without extensive alteration.

The ignition coils currently in use in the automotive industry on thepresent type of D. C. ignitionsystems usually have one high tensionterminal from the secondary winding, and also two low tension terminals,one of which is connected to the battery side of the coil primary andthe other to the breaker point side of the coil primary. It is to thelow tension terminal on the breaker point side of the coil primary ofone of the two coils in the present two-coil system that a post 44 onthe distributor 10 is connected by a suitable conductor 44a. A similarpost 46 is mounted on the distributor 10 and is connected to the lowtension terminal on the breaker point side of the coil primary of theother one of the two coils by means of a conductor 46a. An internalconductor 44h interconnects the post 44 and a connector bracket shown at48. Another internal conductor 46h interconnects thc post 46 to anotherconnector bracket shown at 50. The bracket 48 is connected by a springloaded spiral conductor 52 to a movable electrical contact 54 which isadapted to cooperate with its associated fixed contacts 56. A conductor58 and a conductor 562' connect the fixed contact 56 to a connectorbracket which is shown at 50. The movable contact 54 is mounted at theend of an arm which is cam operated at 59 by means of the eight-lobedcam 32. The connector bracket 48 is connected by means of an internalconductor 60 to one side of an insulated .250 pf. condenser 62. Theother side of the condenser 62 is connected to the connector bracket 5()by another internal conductor 64.

The insulating condenser 62 is mounted to a base plate 63 which ismounted for relative rotation with respect to the rotor shaft 16 for thepurpose of adjusting the timing. The base plate 63 is grounded to thecasing by means of a conductor 65.` A conductive arm 66 having a pair ofspaced-apart contacts thereon is mounted for oscillatory movement bymeans of a conductive spring 68 which is mounted in and grounded througha mounting screw 69 carried by a grounded bracket 70. A conductor 72 isconnected at one end to the connector bracket 48 and at the other end toa contact which is opposed to one of the spaced-apart contacts on thearm 66 and combines therewith to form a set of contacts 76. The springconductor 74 is connected at one end through the conductor 50a to theconnector bracket 50 and is connected at the other end to a contactwhich is opposed` to and combines with the other of the spaced-apartcontacts on the arm 66 to form a second set of contacts 78. The radiallyinner contacts of the pair of contacts 76 is fixed, and the radiallyinner Contact of the set of contacts 78 is cam-operated at 79 by meansof the four-lobed cam 30. The contacts 76 and 78 are preferably formedof silver and are adapted to function as circuit selector contacts whichcooperatetin a manner later to be described more fully. A camming motionat 79 in a radially outward direction causes the contacts 78 to closeand causes the contacts 76 to separate and open. The camming motion at79 in the radially inward direction will cause the contacts 78 to openand the contacts 76 to close by virtue of the action of the springconductor 68.

The contacts 54 and 56 which may be of tungsten, are circuit breakercontacts and have a screw adjustment 80 for controlling the spacingthereof. The circuit selector contacts 76 and 78 have an adjusting screw82 for adjusting the spacing thereof.

Referring to Figures 5, 6, and 7 of the drawings, a spark gap block 24,which is adapted tobe used with the distributor 10 of the preferredembodiment shown in Figure lthroughlS, is shown in detail and includes adepending member which is threadably received at one cud thereof in thedistributor cover 22 and is affixed to' a metallic base 87 for the block24 at the other end thereof. A pair of spaced .001 pj. condensers 86 and88 is secured to the spark gap block 24 at opposite sides thereof andincludes plates 90 which are connected to a ground terminal 92 which inturn is grounded by means of conductors 94. The condensers also includeother plates 96 which are connected to condenser discharge terminals 98which in turn are connected by means of conductors, one of which isshown at 100, to a secondary output terminal of one of the respectiveignition coils. The charged condenser terminal 98 for the condenser 88has a conductor 102 extending therefrom to a secondary output terminalof the other coil of the two-coil system under consideration. Thecharged condenser terminal 98 for the condenser 86 has a conductor 104connecting it to a common plate 105 which supports a pair of spacedapartelectrodes 106 and 108 which form respectively with appropriate lowerelectrodes a set of main electrodes and a set of teaser electrodesrespectively. The charged condenser terminal 98 for the condenser 88 hasa conductor 110 forming a connection therefrom to a plate 109 which isconnected to a pair of spaced-part elec trodes 106 and 108 in a mannersimilar to the foregoing similarly designated electrodes 106 and 108.

Each set of the main electrodes 106 has a gap therein which ismaintained at between 0.025" to 0.041 and adjustable by means of a setof threads which are formed on the outside of the electrodes. The setsof teaser electrodes 108 form a fixed spark gap and are preferablyadjusted to 0.015 by means of a set of threads provided on the outsideof the lower electrodes of each set 108.

The spark gap block 24 has an insulated casing 112, as seen in Figure 7,which is provided with a bore 114. The bore 114 is open to theatmosphere and is effective to establish communication between theatmosphere and both the main spark gaps and the teaser gaps between theelectrodes 106 and 108 respectively. Another bore 116 is formed in theinsulated casing 112 and within which the main electrodes 106 aredisposed. Both ends of the bore 116 are open to the atmosphere therebyestablishing communication between the atmosphere and each of theelectrodes 106 and 108. The current carrying capacity of each set ofmain electrodes 106 far exceeds the capacity of each set of the teaserelectrodes 108. The teaser electrodes are arranged to have in seriestherewith a resistance 108 which function to stabilize the firing of themain electrode 106 at the associated gaps and to ionize the atmospheresurrounding the main electrode gaps immediately prior to firing.

The distributor of the preferred embodiment of Figures lis connected bymeans of a low tension harness, formed of the individual ignition leads26 for each cylinder of the multi-cylinder engine, to a plurality ofspark plug and high tension type transformer units typified by the onehigh tension type unit which is particularly shown at 124 in Figures 8and 9 of the drawings. The transformer unit 124 is contained within agrounded metal tube 1.26 and comprises a long insulating mounting sleeve128. The lead from the wiring harness 26 termi nates in a conductivespring terminal 130 forming a connection with a lead 134 to one side ofa primary transformer winding 136. The winding 136 is wound around aninsulating thimble 138 containing an iron core 140. The primary windingis received within a tubular insulator 142 whch has a conductivemetallic adaptor 151 at the base thereof. The tubular insulator 142 isWound with a transformer secondary winding 144 having a turns ratio withrespect to the primary winding of 11.2:1 and is commonly connected atone side at 146 tothe primary winding. The common connection 146 isgrounded to the grounded metal tube 126 by means of a set of three ormore spring positioning clips 148. The secondary winding 144 isconnected at its opposite end toa metallic.

f6 adaptor 151 which is secured to the tubular insulator 142.; Theadaptor 151 is biased into engagement with a suitable mating conductorby means of a coil spring 158 disposed at the upper end of the tubularinsulator 142. The main conductor receives therein a spring clip 152which is adapted to be removably secured to the upper end of the centerelectrode 154 of a ceramic spark plug 156. The reaction thrust of thespring 158 is absorbed by a clip 160 which holds an insulator 161 andthe insulating sleeve 128 together as a unit.

The operation of the preferred embodiment of the Figures 1-15 is bestunderstood from a consideration of the graphically presented Figures 10,1l, 12, 13, 14 and particularly the overall wiring diagram of Figure l5.The two-coil type ignition system, according to the preferred form ofthe invention, has a set of primary and secondary windings 162 and 164forming the first low tension type transformer or ignition coil 166 anda set of primary and secondary windings 168 and 170 forming the secondlow tension type transformer or ignition coil 172.

The primary windings 162 and 168 are connected at one end to a commonkey-controlled ignition switch 174 leading to a battery 176 which isgrounded at 178. The primary windings 162 and 168 are connected at theiropposite end to the ground 70 by means of the coacting sets of contacts76 and 78 and the contacts 54 and 56. Each of these contacts arecam-operated as previously explained.

Each of the contacts 76 and 78 function as circuit selector contacts andare alternately opened or closed by the four-lobed cam 30. Contact 76opens when contact 78 closes, and closes when the contact 78 opens.v

Neither of the contacts 76 or 78 are adapted to be open when the breakercontact points 54 and 56 are open. Except for an instantaneous time ofoverlap when both sets of contacts 76 and 78 are closed, either one orthe other sets of contacts 76 and 78 is always open and it is only underthis latter condition that the breaker points 54 and S6 will be openedto interrupt the electrical circuit.

Accordingly, the contacts 76 and 78 are actuated immediately prior tothe opening of the breaker points 54 and 56 and are never effective tointerrupt the iiow of electrical energy to or from the transformercoils.

vTiming of the ignition system is controlled at the breaker points 54and 56. Referring to Figure 10, it is seen that both of the low tensiontype transformers 166 and 172 are being energized immediately prior toreaching the zero degree distributor position. Upon reaching zero degreeposition the points 54 and 56 commence to separate thereby interruptingthe flow of current from the battery 176 through the primary of the-coil 172, conductor 46 through the conductor 58, through the spring 52,through conductor 48, through line 72, and.

then to the ground 70 through the contacts 76. Immediately prior to theseparation of the points 54 and 56, ignition current was flowing throughboth of the primaries 162 and 168 and then to the ground at 70 throughthe conductors 44, 46, and 58, spring 52, conductors 48 and 72, arm 66,and spring 68. The circuit to the primary 168 is interrupted by theopening of the breaker points 54 and 56 and is held open by the cam 32during 18 of distributor rotor rotation. Thereafter the breaker points54 and 56 will close and the primary 16.8 will again be come energized.Throughout the time that the circuit for the primary 168 was beingopened and closed, the

primary 162 was continually being energized without in' ananas 7 openingand the closing of the contacts 76 and 78 respectively, occurssubstantially at the same instant.

The alternating action of the selector contacts 76 and 78 may occur atany instant during the rotation of the distributor rotor within theadditional twenty-seven degrees of rotation previously mentioned.Therefore, the timing of the operation of the contacts 76 and 78 withrespect to the operation of the breaker contacts 54 and 56 is notcritical and no service problem is involved.

After the distributor rotor undergoes 45 of total rotation from the zeroposition, the breaker points 54 and 56 are again opened by the cam 32thereby causing an interruption in the ow of primary ignition currentthrough the coil 162 to the ground 70 through the contact 78.Immediately prior to the opening of the contacts 54 and 56, both thecoils 162 and 168 are being energized by theA ignition current owingthrough the respective primaries and the conductors 44 and 46, thespring S2, the conductors 50 and 74, and the spring 68 to the ground 70.During the time that the breaker points 54 and 56 are interrupting theignition current in primary 162, the primary 168 is being continuouslyenergized. The contacts 54 and 56 are held open to interrupt the primarycurrent in coil 162 during an additional 18 distributor rotor rotation.When this latter 18 of distributor rotation is completed, the ignitioncurrent again commences to energize the primary 162 while at the sametime the ignition current in the other primary circuit continues toenergize the coil 168.

The induced voltage which is built up in the secondariest 164 `and 170is impressed across the condensers 86 and 88 respectively, during theopening and closing of the associated primary circuits. It is thus seenthat the condensers 86 and 88 are alternately charged in the samesequence as the operation of their associated coils. When a sufficientcharge is built up in either of the condensers 86 or 88, the teaserdischarge gap between the electrodes 108 is broken down thereby causinga spark to jump across the same. The presence of this spark in theteaser gap is effective to ionize the atmosphere surrounding thedischarge gap between electrodes 106 thereby allowing a surge of highfrequency current to pass through these electrodes into the distributor34 to one of a plurality of spark plug loads. A teaser gap and a maindischarge gap are provided for each of the ignition coils 166 and 172and function alternately in the same sequence as the operation of theirassociated coils.

This same operating cycle continues in this fashion until eight separatecondenser discharges occur during one cornplete revolution of thedistributor rotor which corresponds to 720 of engine crankshaft rotationthereby causing the tiring of all eight cylinders of the V-8 engineselected for the purpose of illustrating the present invention.

It is to be noted that each of the transformer coils 166 and 172 isabsorbing` and continuously accumulating energy for 72 successivedegrees of distributor rotation during each quarter turn of thedistributor rotor. Accordngly, during 80% of the operating time cach ofthe coils isstoring electrical energy and during only 20% of theoperating time the coils are discharging and releasing this energy.`Because of the fact that ignition coils are continuously accumulatingelectrical energy during a majority of the operating time, the presentinvention is particularly adapted for use during high speed operation ofthe internal combustion engine. If the ignition coils are notcontinuously energized during a substantial portion of the operatingtime an insufficient charge will be accumulated prior to the firing ofthe cylinders.

It is to be further noted that during each successive opening of thebreaker points S4 and 56 the current being interrupted is of a differentdirection than that of the preceding interrupted current. Hence, noappreciable transfer of metal is likely to occur over a period betweenthe tungsten points 54 and 56.

' Because of the fact that the contacts 76 and 78 'open 8 prior totheopening of the breaker contacts 54 and 56, no spark will occur ateither of these points. Therefore, the contacts 76 and 78 may be formedof silver since no problems of metal transfer are present.

The secondary windings 164 and 170 of the low tension type ignitioncoils 166 and 172 may be connected to the respective primary windingsthereof at either the battery side or to the breaker point side of thelatter, but in the illustrated example shown in Figure l5 the secondarywindings are connected respectively at 180 and at 182 to the breakerpoint side of the windings 162 and 16S in the primary circuit. Theoutput sides 184 and 186 of the secondary coils 164 and 170 respectivelyare connected by the conductors 100 and 102 to the charged condenserterminals 98 for the pair of spaced apart discharge condensers 86 and88. A pair of R. F. choke coils 188 and may be provided in theconductors 100 and 102 respectively, to eliminate any radio frequencieswhich may be generated in the condenser circuits from being fed backinto the transformer circuit. When the secondary winding of each of thetransformer coils 166 and 172 discharges, a charge is alternately builtup across the respective condensers 86 and 88 and also across therespective pairs of the electrodes 106 and 108. It will be appreciatedthat the magnitude of the charge which is stored up in the ,001 nf.condensers 86 and 88 will be relatively low in comparison to the chargewhich is capable of beingT stored up in the higher capacity condenser 62connected between the conductors 48 and 50.

In the operation of the ignition system of the present invention, thevoltage on each of the condensers 86 and 88 is allowed to build up to avalue which is sufficient t0 alternately re the main gaps 106.Immediately prior to the ring of these gaps, the respective teaser gapsbetween the electrons 108, as appropriate, tire and ionize theatmosphere adjacent to the main gaps which cause the latter to fire atthe comparatively low and stable tiring voltage of 2,000 volts. The maingaps fire alternatively, as previously described, and the energydischarge thereacross is distributed by means of the brush-typedistributor 34 to the high-tension type transformer coils 136 and 134associated with each of the spark plugs. The turns ratio of 11.211 inthe transformer windings 136 and 144 causes a step-up in the low tensionvoltage to an effective voltage between 15,000 and 20,000 volts which issufiicient to tire each of the plugs 156. The amperage across each sparkplug gap is approximately 3 amperes.

The oscillograms reproduced at Figures ll, l2, and 13 represent thecharacteristics of the voltage across each discharge condenserimmediately prior and immediately following the tiring of the spark gapassociated with each of the respective condensers. The condensers maydischarge several times during the time interval immediately followingthe opening of the distributor breaker contacts at 54 and 56. It hasbeen found that as many as l5 successive condenser discharges may beproduced. Each of the individual discharges, which are graphicallyrepresented in Figure l1, produces a separate discharge at the sparkplug.

The induced voltage in thc secondaries of each of the distributor coils166 and 172 causes a voltage rise across each of the respectivecondensers which is followed by a condenser discharge. When each of thecondensers are discharged, the voltage thereacross is reduced to a lowvalue, which is indicated at 194 in Figure 1l. The trans former at theinstant that the voltage reaches the point 194 is still discharging andthereupon causes the voltage across cach of the respective condensers torise again to a new peak value, indicated at 192, in Figure ll. Theapproximate time which elapses between the occurrence of each of thepeak voltages is approximately 250 n seconds. The time elapsing duringeach condenser discharge, which corresponds to a drop in the voltagecui-ve of Figurell from A196 to 194, is approximately one ,L second. -v

As seen in Figure ll, an oscillatory voltage is set up as at 198 afterthe previously described series of condenser discharges occur. Thisoscillatory voltage has a frequency of approximately 660 cycles persecond and it continues until such time as the breaker points 54 and 56close. After the points 54 and 56 close, as indicated at 199 in Figurel1, a highly damped oscillatory circuit results having a frequency ofapproximately 1660 cycles per second. Under certain conditions, thefixed gaps at 106 and S may fail to deionize after the initial spark andan arc (uni-directional current) will form supplied by cur rent from thedischarging transformer. This arc, the picture form of which is broughtout in the oscillogram of Figure l2, will persist until the current isinsucient to maintain the arc. The condition of the gap electrodesurfaces and the type of atmosphere surrounding the gap apparently arethe controlling factors in striking and maintaining such an arc.

The number of recurrent sparks obtained during one opening of thebreaker points will vary with the voltage and with the energy availablefrom the condenser charging source. The energy available in turn varieswith the Voltage of the car battery and with engine speed. The number ofsparks which may be obtained is variable depending upon theabove-mentioned factors. In the oscillogram shown in Figure 13, only onespark is obtained,

and at the termination thereof an insufficient amount of energy isavailable to produce another charging curve, as at 196, and thefunctioning of the condenser degenerates into the 660 cycle oscillationshown at l198 which is in turn followed by the 1660 cycle oscillationscommencing with the closing of the points 54 and 56, as shown at 199.

In Figure 14 is shown an oscillogram with a magnified scale whichrepresents the behavior of each of the condensers during the one nsecond time interval in which the condenser is discharging. During therising portion of the charging curve shown at 196, which lasts forapproximately 250 ,u seconds, the voltage across the dischargecondensers is built up to a peak at 192 of approximately 2,000 voltswhereupon a rapid spark discharge occurs having a frequency ofapproximately 5 megacycles. This high frequency discharge is stamped outduring the previously mentioned one ,u second time interf val.Thereafter, the spark gaps will deionize provided the conditions aresuch that this is made possible and the voltage again begins to riseaccording to the curve 196 across the discharge oondensers. In the caseof recurrent spark discharges, this voltage rise will require another250 ,u seconds.

The high frequency condenser discharge, shown in Figure 14, isduplicated at the spark plugs after the ignition voltage is stepped upby the transformers associated with each of the plugs. This recurrenthigh frequency spark produced at each plug is particularly suited forigniting fuel mixtures which may be partciularly hard to ignite.

A modified form of the present invention is illustrated by means of awiring diagram shown in Figure 16. This diagram includes a key controlignition switch 274 which is connected to a battery 276 which in turn isgrounded at 278. The switch 274 is connected to a pair of parallelinductances consisting of one separate primary choke 266 and anotherseparate primary coke 272. A condenser 262, which has a capacitance of.250 uf. is connected between the output ends'of the chokes 266 and 272.Two sets of cam operated selector contacts 294 and 296, both of whichare grounded at 270, are connected between the output ends of the chokes266 and 272 in parallel relationship with the condenser 262. One set ofcam operated breaker points 254 and 256 are also connected between theoutput ends of the chokes 266 and 272.

The breaker points and circuit selector contacts inthe modified form ofthe invention, shown in Figure, 16v, are.

10 similar to the associated breaker points and selector con'- tactsdescribed in connection with the embodiment shown in Figure 15. Thecircuit selector contacts 294 and 296 and the breaker points 254 and 256operate in conjunction with one another in much the same manner as specified in the preceding embodiment in that each time the breaker points254 and 256 open, a voltage build-up across either the choke 266 or thechoke 272 thereupon becomes available for supplying energy into thebalance of the circuit. Also, the circuit selector contacts'294 and 296are arranged to be opened alternately and selectively with respect toeach other as in the preceding embodiment. In other words, immediatelypreceding the opening of either set there is an instantaneous period ofoverlap in the cycle during which both sets of contacts are closed.Also, these selector contacts 294 and 296 open so always to precede theopening of the breaker points 254 and 256.

The timing of the system is effected at the breaker points 254 and 256.These points are arranged between the chokes 266 and 272 so that theyare subjected to an alternating polarity and for that reason there is noappreciable transfer of metal between these points, which preferably areformed of tungsten.

The voltage alternately builds up across the primary chokes 266 and 272and is impressed across a primary winding 262' of a low tension typeclosed core transformer 268. The transformer 268 has a secondary winding264, one side of which is connected at 298 to the primary winding 262',and the other side of which supplies a brush-type distributor 234arranged for service in an 8-cylinder engine. A secondary R. F. chokecoil 288 and a fixed spark gap 206 in series therewith are interposedbetween the secondary of the transformer 268 and the distributor 234. Acondenser 286 having a capacity of .001 nf. has one side thereofconnected between the choke coil 288 and the gap 206 and the other sideconnected to the ground. A high resistance xed teaser gap 208 isprovided in parallel with the main xed spark gap 206 in order tostabilize the operation of the latter.

In operationthe voltage alternately built up across the separate primarychokes 266 and 272 is impressed across the primary winding 262' of thelow tension trans` former 268 Whose secondary winding 264 charges thecharging condenser 286 to a voltage suicient to ionize` the teaser gap208 and break down the main discharge gap 206 which allows a surge ofhigh frequency current to pass to the brush-type distributor 234 forfurther dis.- tribution to the load. In the present instance, the loadcomprises transformer-type spark plug units, one for each cylinder ofthe engine and including a high tension transformer, shown at 236 and244, which is grounded on one side, as indicated at 226, and which firesa spark plug 256. The spark plug and transformer unit is the same as theunit of the preceding Figures 8 and 9, and have a primary to secondaryturns ratio of approximately 11.2: 1. The relatively low output voltageon the output side of the low tension type transformer 268 is of theorder of 2,000 volts, and is transformed by means of the high tensiontransformer 236, 244'into a voltage of approximately 15,000 to 20,000volts which is available at the spark plug 256. Each spark dischargeacross the gap 206 and its corresponding spark across the spark plug gap256' have a steep wave front and are characterized by a high' dischargefrequency of approximately 5 megacycles.

In Figure 17, the modified wiring diagram there shown,`

corresponds in all major particulars to the diagram of the precedingembodiment of Figure 16 in that it includes a three-point cam-operatedswitching circuit 394, 396, 354, a low tension type closed coretransformer 368, a 4condenser 386, and a spark plug and transformerunit336, 344, 356. In the embodiment of Figure 17, however, the distributoris of the jump spark type having a rotor 334 which forms two rotatingspark gaps between the electrode tip thereof and each of the individualcontacts in the distributor cover for the cylinders lof the engine. Amain spark gap 306 is provided together with a teaser gap 308. Theelectrode at the teaser gap has a grounded high resistance therein andmoves with the rotor 334.

In the embodiment of Figure 17, the operation is the same as that of thepreceding embodiment of -Figure 16, and the timing of the ignitionsystem is likewise effected at the breaker point 354 and 356. Themomentary period in which the electrode tip of the distributor rotor 334passes each fixed contact in the distributor cover is more thansufiicient to transmit the high frequency current to the primary winding336 of the spark plug transformer unit. A surge of current of therelatively low voltage of 2,000 volts through the gap 306 occurs with afrequency of `the magnitude of approximately megacycles, and acorresponding surge of cur rent of the relatively high voltage of 15,000to 20,000 volts atn the spark plug 356 occurs with a frequency of thesame magnitude of approximately 5 megacyelcs. The resulting spark at thespark gap 356 has a very steep and pronounced wave front. The previouslydescribed low tension characteristic is again retained in the embodimentof Figure 17, it being noted that a current with a relatively lowvoltage of 2,000 volts is distributed by the distributor 334 from thelow-voltage-type transformer 36S.

In Figure 18, a spark gap unit comprising a pair of sets of main andteaser electrodes 206 and 208 respectively is shown which is suitablefor the embodiment of `the preceding Figure 16 and which, if used ingroups of two pairs of sets per system, is also suitable for themultiple fixed gap arrangement of the preceding Figure l5. The mainelectrodes 206 are adjusted by appropriate movement of the threadedupper electrode thereof to provide a gap at 214 having a measurement of.025 to .041". The set of teaser electrodes 208 is arranged to have anadjustable spaced-apart relationship to provide a gap at 216 having ameasurement of approximately .015.

The spark gap unit has an electrode-holding insulating body 224 having ahollow interior 217. The upper electrode of the electrode set 206 islocked in its adjusted position by a locknut 220 which clamps a plate205 to the top of the insulating body 224 so as to interconnect theupper electrodes 206 and 208. The gaps 2.14 and 216 are disposed in thecommon chamber provided by the hollow interior 217 of the insulatingbody 224 which communicates to the atmosphere by means of a vent 215. Ametal plate 218 is provided at the base of the insulating body 224 andsupports the lower electrode of the main set 206 and also the lowerelectrode of the teaser set 208 which is adjustably locked thereto bymeans of a lock nut 222. A threaded depending portion 285 is carried bythe plate 218 to provide a means for mounting the spark gap unit at thetop of the cover over the distributor rotor 234.

Another modified form of the present invention is shown in Figure 19which is somewhat similar to the form previously described in connectionwith Figures l through l5. dual breaker point type as distinguished fromthe three point systems described previously.

The points 454 and 456 of the present modified form are effective tointerrupt the liow of ignition current through the primaries 462 and 468of the ignition 466 and 472 respectively, and to control the ignitiontiming. The points 454 and 456 are positioned so that they are openedalternatively with respect to each other. The condensers 462 and 462 areconnected between the ground and the breaker point side of each of thecoils 472 and 466 respectively and are effective to reduce in the usualmanner the tendency of the associated breaker points to arc due to theself-induced voltage in the coil primaries.'

This modified form is of the double coil The coil secondary circuits areidentical in most respects to the secondary circuits for the embodimentof Figures 1 through 15 and need not be further described in detail.

Upon interruption of the current flowing through the coil primaries theresulting induced voltage in the associated secondaries alternatelycharge the condensers 486 and 488. The condensers 486 and 488 dischargethrough the spark gaps as previously pointed out in connection with theother forms of the invention. It has been found that the current whichsurges across one set of main gaps and teaser gaps will not break downthe other gaps and discharge the other discharge condenser before itcauses a spark to jump across those other gaps. It is thus seen that thespark gaps 408 and 406 function in the same manner as the correspondinggaps 108 and 106, shown in Figure l5, to rectify the secondary current.lt is thus seen that the gaps 408 and 406 are effective to eliminate theneed for using expensive rcctificrs.

The various embodiments of the invention are shown herein adapted to ahigh speed 8-cylinder internal coni bustion engine. It is evident thatthe invention will be equally effective in other multi-cylinder sparkengine arrangements, particularly other high speed engines. Also, thedrawings show a transformer-type spark plug in which the transformer andspark plug proper are of separate constructions and ultimatelyfabricated or assem bled together in a common container. However, atransformer-type spark plug can be used in which the transformerwindings are actually internally incorporated in the top or porcelainportion of the spark plug itself and thus become a physical partthereof.

The operation of the present invention does not depend upon or requirethe specific type of spark plug and transformer unit which isillustrated in Figure 8. lt would be possible to employ a standard sparkplug or other ignitor means with the present invention and to interposean independent step-up transformer between the distributor and thisignitor means. Also, it is conceivable that the use of the step-uptransformer might be eliminated entirely in those cases where only asmall spark voltage is required.

n The spark plug and transformer unit is shown enclosed 1n a groundedmetal tube 126, but indeed, it is not essential to the invention thatthe spark plug and transformer unit be thus shielded. On the other hand,it might be found advantageous not only to shield the spark plug andtransformer unit in this manner, but also to shield all the individualleads 26 of the ignition harness. In the latter case, the presentinvention is particularly advantageous in that the distribution circuitsare of the low tension type and therefore, the shielding nrescnts littleor' no problem in connection with electrical losses in the system due tostray capacity.

Variations within the spirit and scope of the invention are equallycomprehended by the foregoing description.

What we claim is:

1: In an ignition system for an internal combustion engine, a pair ofcapacitors each having a source of charging power, a plurality ofcombustion ignitor means, a capacitor-energy distributor for conductingenergy to the individual ignitor means in rotation, circuit meansconnecting one of the respective capacitors and said distributor andcircuit means connecting the other of the respective capacitors and saiddistributor and each said circuit means including an intervening sparkgap between the distributor and the corresponding capacitor, andinterconnection means effective between said sources of charging powerto cause the latter to charge said capacitors and impress aunidirectional voltage and of identical polarity across said gapsalternatively for firing the same thereby causing a correspondingpotential to be applied tothe individual ignitor means in rotation inthe above described manner and having the same polarity for all saidignitor means.

2. For use in an internal combustion engine including therewith aplurality of fuel ignitor means, a pair of alternately chargedcapacitances, means forming pluralities of spark gap paths differentones of which are connected to and lead from each of said capacitances,and a common switch in series with said pluralities of spark gap pathsfor distributing energy from said capacitances in rotation to successiveones of vsaid ignitor means, said pair of alternately chargedcapacitances having means providing an unidirectional ow of energythereto for alternately charging the same with Voltage charges of likesign.

3. In an internal combustion engine ignition system having a fuelignitor means, a source of electrical energy, and a distributormechanism for distributing electrical energy from said source to saidignitor means; a circuit means interconnecting said power source andsaid distributor mechanism; said circuit means comprising a pair ofignition coils, breaker means for opening and closing composite portionsof said circuit means in a predetermined operative sequence therebycausing a voltage to be alternately and successively built up in saidignition coils, a capacitor electrically connected to said ignitioncoils and adapted to be energized thereby, and a main spark gap meanscomprising a pair of main arcing terminals, one of said terminals beingconnected to said capacitor and the other of said terminals beingconnected to said distributor mechanism, said capacitor being operativeto discharge electrical energy through said spark gap means to saiddistributor mechanism, said spark gap means including teaser arcingterminals connected in parallel with respect to said main arcingterminals.

4. In an ignition system for an internal combustion engine, an ignitioncoil primary circuit and a secondary circuit including a pair of primarywindings and a pair of secondary windings respectively, each of saidprimary windings being electrically coupled to a separate one of saidsecondary windings, a source of electrical potential operativelyconnected between said primary circuit and ground for energizing saidprimary windings, breaker means for opening and closing separateportions of said primary circuit in a predetermined operative sequenceto alternately deenergize said primary windings whereby an inducedvoltage is alternately built up in said secondary windings and wherebyone of said primary windings is continuously being energized during thetime interval in which the lother is being deenergized, said secondarycircuit including a pair of capacitors, a separate one of saidcapacitors being connected between each secondary winding and ground,interconnecting one portion thereof and the ground, a rectifying meansconnected to one side of each of said capacitors, and means connected tosaid rectifying means for distributing ignition current throughout theignition system, said capacitor being adapted to discharge a highfrequency ignition currenty through said rectifying means.

5. The combination as set forth in claim 4 wherein said rectifying meanscomprises a pair of main electrodes spaced apart to form a main sparkgap therebetween,'

and a teaser electrode connected in parallel across said main electrodesto form a teaser spark gap to initiate an arc across said mainelectrodes at low voltage.

6. In an ignition system for an internal combustion engine, an ignitioncoil primary circuit including two said windings, a source of electricalenergy operatively connected between said primary circuit and ground forenergizing said windings, breaker means for opening and closing saidprimary circuit in a predetermined operative sequence therebyalternately deenergizing said windings, a secondary circuit including atleast one winding elec trically coupled to said primary circuit and acapacitor interconnecting said secondary circuit winding to ground,

a spark gap means connected to only one side of said capacitor, and ameans4 connected to said spark gap means for .distributing ignitioncurrent throughout the .r

A.14 ignition system, said ignition current passing across said sparkgap means'in only one direction, said capacitor being adapted todischarge a high frequency ignition cir# cuit through said spark gapmeans, said spark gap means comprising a first pair of electrodes spacedapart to form a main spark gap therebetween, and a teaser spark gapformed between a second pair of electrodes connected in parallel withrespect to said iirst pair of electrodes and in close proximity thereto,said teaser gap being of a smaller dimension than said main gap.

7. In an ignition system for an internal combustion engine, an ignitioncoil primary circuit, an ignition coil secondary circuit electricallycoupled to said primary circuit, a source of electrical potentialoperatively connected between said primary circuit and ground, breakermeans for opening and closing separate portions of said primary circuitin a predetermined operative sequence, said secondary circuit includinga capacitor interconnecting one portion thereof and ground, a spark gapmeans connected toone side of said capacitor, and a means connected tosaid spark gap means for distributing ignition current throughout theignition system, said capacitor being adapted to discharge a highfrequency ignition circuit through said spark gap means, said spark gapmeans comprising a first electrode means having spaced apart portionsforming a main spark gap therebetween, a second electrode means defininga teaser spark gap, said second electrode means being connected inparallel with respect to said first electrode means and in closeproximity thereto, said teaser gap being of a smaller dimension thansaid main gap, and an electrical resistance connected in series withsaid second electrode means.

8. In an ignition system for an internal combustion engine, a pair ofignition transformer coils including primary and secondary coilportions, a pair of ignition current rectifying means, a secondarycircuit means interconnecting a separate one of said pair of rectifyingmeans with each of said secondary coil portions, a primary circuitconnected to` said primary portions and including circuit breaker pointstherein, a source of electrical potential connected between said primaryportion and ground, a iii-,stv rotary cam means for actuating saidbreaker points, said primary circuit further including con' tactmeansfor alternately connecting each of said pri-A mary coil portions toground, a second rotary cam means for actuating said contact means, saidbreaker points and said contact means being adapted to alternately andseparately deenergize each of said primary coil portions while the otherprimary coil portion is being energized, and a pair of capacitors, aseparate one of said capacitors being connected between each of saidsecondary portions and ground, said secondary coil portions beingeffective to produce an induced voltage to charge the capacitors therebycausing a surge of current to alternately pass through each of saidrectifying means.

9. In an ignition system for an internal combustion engine having anignition current distributor and source of ignition current, a pair ofignition coils, an ignition transformer coil, a circuit connecting saidcoils with said source, breaker means interposed in said circuit forsuccessively interrupting the same, electrical contact means interposedin said circuit for reversing the polarity of said ignition transformercoil portion, said contact means being adapted to be actuatedimmediately prior to the breaking of the circuit by said breaker means,a secondary coil circuit electrically coupled with said ignitiontransformer coil and interconnected with said distributon a main sparkgap interposed in said secondary circuit, and a capacitor connectingsaid secondary circuit to the ground, said distributor including thereina plurality of xed contacts and a rotary electrode, said main spark gapbeing formed between said rotary electrode and said fixed contacts. A'

l0. The combination as set forth in claim 9 wherein said distributor hasdisposedtherein a second teaser electrode rotatably mounted in parallelrelationship with respect to said first mentioned rotary electrode, saidteaser electrode cooperating with said rotary electrode to form a teaserspark gap in close proximity to said main spark gap.

11. ln an automotive ignition system, a pair of capacitors each having asource of charging power, a plurality of spark plug transformers, acapacitor-energy distributor for conducting energy to the individualspark plug transformers in rotation, `circuit means connecting one ofthe respective capacitors and said distributor and circuit meansconnecting the other of the respective capacitors and said distributorand each said circuit means including an intervening spark gap betweenthe distributor and the corresponding capacitor, and interconnectionmeans effective between said sources of charging power to cause thelatter to charge said capacitors and impress a unidirectional voltageand of identical polarity across said gaps alternatively for firing thesame thereby causing a corresponding potential to be applied to theindividual spark plug transformers in rotation in the above describedmanner and having the same polarity for all said transformers.

12. In an automotive ignition system, a pair of capacitors each having asource of charging power, a plurality of spark plug transformers, acapacitor-energy distributor for conducting energy to the individualspark plug transformers in rotation, circuit means connecting one of therespective capacitors and said distributor, and circuit means connectingthe other of the respective capacitors and said distributor and eachsaid circuit means including an intervening spark gap between thedistributor and the corresponding capacitor, and interconnection meanseffective between said sources of charging power to cause the latter tocharge said capacitors and impress a unidirectional voltage of identicalpolarity across said gaps alternatively for firing the same therebycausing a corresponding potential to be applied to the individual sparkplug transformers in rotation in the above described manner and havingthe same polarity for all said transformers, each said circuit meansfurther `including a stabilizing spark gap in parallel with the firstnamed gap thereof for stabilizing the firing voltage of the same inorder to cause the individual potentials applied to all said spark plugtransformers to be uniform.

13. In an automotive ignition system, a pair of capacitors each having asource of charging power, a plurality of spark plug transformers, acapacitor-energy distributor for conducting energy to the individualspark plug transformers in rotation, circuit means connecting one of therespective capacitors and said distributor, and circuit means connectingthe other of the respective capacitors and said distributor and eachsaid circuit means including an intervening spark gap between thedistributor and the corresponding capacitor, interconnection meanseffective between said sources of charging power to cause the latter tocharge said capacitors and impress a unidirectional voltage and ofidentical polarity across said gaps alternatively for ring the samethereby causing a corresponding potential to be applied to theindividual spark plug transformers in rotation in the above describedmanner and having the same polarity for all said transformers, each saidsource of charging power being formed` of windings including anenergizable input winding in parallel with the other energizable inputwinding of the other source of charging power, and circuit means forconnecting said paralleled input windings to a common energy so-urceincluding sets of contacts cooperating to cause the substantiallycontinuous storing of energy in the input windings and adapted to berecurrently opened according to predetermined sequence to cause thesources of charging power each alternatively to make available to thecorresponding capacitor the stored energy in the respective input coilthereof.

14. In an automotive ignitiond system, capacitance asi-9,428

means, a plurality of spark plug transformers, means comprisingswitching means for conducting energy from the capacitance means to theindividual spark plug transformers in rotation and including a seriesspark gap effective therein, means for supplying charging power for thecapacitance means and including transformer secondary winding means forrecurrently impressing a voltage on said spark gap and said capacitancemeans for building up the potential on the latter and causing the sameto discharge through the spark gap and apply a corresponding potentialto the spark plug transformers, means including a pair of parallelsimilar windings adapted to cause voltages to be induced across saidtransformer secondary winding means upon being energized, and circuitmeans for connecting said paralleled windings to a D. C. energy sourceand including sets of contacts cooperating to cause the substantiallycontinuous storing of said source energy in the paralleled windings, onesaid set of contacts being adapted to be opened in predeterminedsequences with respect to the others to open circuit said windingsalternatively from said energy source, thereby successively interruptingcurrents of different directions.

15. In an automotive ignition system, capacitance means, a plurality ofspark plug transformers, means comprising switching means for conductingenergy from the capacitance means to the individual spark plugtransformers in rotation and including a series spark gap effectivetherein, means for supplying charging power for the s capacitance meansand including transformer secondary Winding means for recurrentlyimpressing a voltage on said spark gap and said capacitance means forbuilding up the potential on the latter and causing the same todischarge through the spark gap and apply a corresponding potential tothe spark plug transformers, means including a pair of paralleledsimilar windings adapted to cause voltages to be induced across saidtransformer secondary winding means upon being energized, and circuitmeans for connecting said paralleled windings to a D. C. energy sourceand including sets of contacts cooperating to cause the substantiallycontinuous storing of said source energy in the paralleled windings, onesaid set of contacts being adapted to be opened in predeterminedsequences with respect to the others to open circuit said windingsalternatively from said energy source, thereby successively interruptingcurrents of different directions, said transformer secondary windingmeans being of two-part construction, one said part thereof and one saidparalleled winding cooperating to form a first transformer and the othersaid part thereof and the other said paralleled winding cooperating toform a second transformer.

16. ln an automotive ignition system, capacitance means, a plurality ofspark plug transformers, means comprising switching means for conductingenergy from the capacitance means to the individual spark plugtransformers in rotation and including a series spark gap effectivetherein, means for supplying charging power for the capacitance meansand including transformer secondary winding means for recurrentlyimpressing a voltage on said spark gap and said capacitance means forbuilding up the potential on the latter and causing the same todischarge through the spark gap and apply a corresponding potential tothe spark plug transformers, means including a pair of paralleledsimilar windings for causing voltages to be induced across saidtransformer secondary winding means upon being energized, and circuitmeans for connecting said parallel windings to a D. C. energy source andincluding sets of contacts cooperating to cause the substantiallycontinuous storing of said source energy in the paralleled windings, onesaid set of contacts being adapted to be opened in predeterminedsequences with respect to the others to open circuit said windingsalternatively from said energy source, thereby asianssuccessivelyinterrupting currents, of ,different directions, saidtransformer secondary winding means and said capacitance means eachbeing of two-part construction, one said secondary winding part and onesaid paralleled winding cooperating to form a first transformer forcharging one said capacitance part and the other said secondary windingpart and the other said paralleled winding cooperating to form a secondtransformer for charging the other said capacitance part.

17. For use in a multicyli-nder engine having a spark plug andtransformer unit for each cylinder thereof,v a pair of alternatelycharged capacitances, means forming pluralities of spark gap paths`differentones `of which are connected to and lead from each` of saidcapacitances,y and ya common switch in lseries with said pluralities ofspark gap paths for distributing energy from said capacitances inrotation to successive onesr of said spark plugl and transformer units,said pair of alternately charged capacitances having means providing aunidirectional ii'ow of energy thereto for alternately charging the samewith voltage charges of like sign.

18. For use in a multi-cylinder engine having a spark plug andtransformer unit for each cylinder thereof, a pair of alternatelycharged capacitances, means forming pluralities of spark gap pathsconnected to and leading from said capacitances, and a common `switch inseries with said pluralities of spark gap paths for distributing energyfrom said capacitances successively to alternate ones of said spark plugand transformer units, said alternately charged capacitances each havingenergy providing means providing a unidirectional flow of energyythereto and cooperatingl with the other energy providing means foralternately charging the capacitances with potential charges of likesign, both said energy providing means having a common source of D. C.power in series therewith.

19. For use in a multicylinder engine having a spark plug andtransformer unit for each cylinder thereof, a pair of alternatelycharged capacitances, means forming pluralities fof spark gap pathsconnected to and leading from said capacitances, and a common switch inseries with said pluralities of spark gap paths for distributing energyfrom said capacitances successively to alternate ones of said spark plugand transformer units, said alternately charged capacitances each havingenergy providing means providing a unidirectional liow of energy theretoand cooperating with the other energy providing means for alternatelycharging the capacitances with potential charges of like sign, both saidenergy providing means having a common source of D. C. power in seriestherewith, and comprising a pair of paralleled transformers.

20. In an electrical ignition system for a multicylinder engine having aspark plug and transformer for each cylinder thereof, a source of D. C.power, first and second primary windings, and circuit means forconnecting said first and second primary windings to said power sourcesuch that the former are in parallel with one another, said circuitmeans including one set of contacts and other sets of contacts, saidother sets of contacts being effective to close and open in alternation,when said one set of contacts is closed, for storing energy in saidprim-ary windings a majority of the time, all sets of contacts aforesaidhaving cam means establishing cooperation in timed relation thereamongto open said one set of contacts and alternately open circuit, saidenergy storing first and second primary windings; the combination withsaid first and second primary windings, of secondary winding meansforming therewith first and second transformers respectively, acapacitance connected to the first transformer and a capacitanceconnected to the secon-d transformer so as to be charged in sequencewith the aforesaid stored energy when the respective first and secondprimary windings thereof are alternately opencircuited, a switch meansfor distributing energy to the spark plug and transformer for eachcy'linder in rotation, and circuit means connecting each saidcapacitance and said switch means and yhaving a common portion, saidcircuit means including a spark gap between each said capacitance andsaid common portion for preventing the discharge from one capacitancedue to breakdown of the spark gap associated therewith, to interferewith the charging of the other capacitance.

2l. In an electrical ignition system for a multicylinder engine having aspark plug and transformer for each cylinder thereof, a source of D. C.power, first and second primary windings, and circuit means forconnecting said first and second primary windings to said power sourcesuch that `the former are in parallel with one another, said circuitmeans including one set of contacts and other sets of contacts, saidother sets of contacts being effective to close and open in alternation,when said one set of contacts is closed, for storing energy in saidprimary windings a majority of the time, al'l sets of contacts aforesaidhaving cam means establishing cooperation in timed relation thereamongto open said one set of contacts and alternately open circuit saidenergy storing first and second primary windings; the combination withsaid first and second primary windings, of secondary winding meansforming therewith first and second transformers respectively, acapacitance connected to the first transformer and a capacitanceconnected to the second transformer so as to be charged in sequence withthe aforesaid stored energy when the respective first and second primarywindings thereof are alternately open-circuited, a switch means fordistributing energy to` the spark plug and transformer for each cylinderin rotation, and circuit means connecting each said capacitance and saidswitch Ameans and having a common portion, said circuit means includinga main spark gap between each said capacitance and said common portionfor preventing the discharge from one capacitance due to breakdown ofthe spark gap associated therewith, to interfere with the othercapacitance, said circuit means further including stabilizing gaps onein parallel with each main gap for making uniform the firing voltagenecessary to cause breakdown of the main gaps.

22. In an electrical ignition system for a multicylinder engine having asource of D. C. power, first and second primary windings, and circuitmeans for connecting said first and second primary windings to saidpower source such that the former are in parallel with one another, saidcircuit means including one set of contacts and other sets of contacts,said other sets of contacts being effective to close and open inalternation, when said one set of contacts is closed, for storing energyin said primary windings a majority of the time, all sets of contactsaforesaid having cam means establishing cooperation in timed relationthereamong to open said one set of contacts and alternately opencircuit, said energy storing first and second primary windings; thecombination with said first and second primary windings, of secondarywinding means forming therewith first and second transformersrespectively, a capacitance -connected to the first transformer and acapacitance connected to the second transformer so as to be charged insequence with the aforesaid stored energy when the first and secondprimary windings thereof are alternately open-circuited, spark plugs ofa number corresponding to the number of cylinders in `the engine, eachsaid spark plug having a voltage step-up transformer therefor forincreasing a relatively low voltage to a voltage high enough to fire thespark plug, switch means for communicating a relatively low voltage tothe spark plug transformers in rotation, and circuit means connectingeach said capacitance and said switch means and having a common portion,said circuit means providing for the impression of a relatively lowdischarge voltage from each said capacitance upon said switch means andincluding a spark gap between each capacitance aforesaid and said commonportion for essere@ 19 preventing the discharge fromone capacitance dueto breakdownl of the spark gap associated therevvith to change thecharge on the other capacitance.

23. In an ignition system for an internal combustion engine, a pair ofprimary coil windings, a source of electrical potential, said primarywindings being connected in parallel with one side thereof beingconnected to one side of said potential source, a tirst circuit branchconnecting one of said primary windings to the other side of saidpotential source, a second circuit branch connecting the other of saidprimary windings to said other side of said potential source, firstbreaker elements for interrupting said first circuit branch and secondbreaker elements for interrupting said second circuit branch, means forseparating said first breaker elements While simultaneously closing saidsecond breaker elements and for separating said second breaker elementswhile simultaneously closing said iirst breaker elements, a thirdcircuit branch interconnecting the other sides of said primary windings,third breaker elements disposed in said third circuit branch, and meansfor alternately separating and closing said third breaker element whilesaid first breaker elements are closed and while said second breakerelements are closed.

24. In an ignition system for an internal combustion engine, a pair ofprimary coil windings, a source of e1ectrical potential, said primarywindings being connected in parallel with one side thereof beingconnected to one side of said potential source, a first circuit branchcon necting one of said primary windings to the other side of saidpotential source, a second circuit branch connecting the other of saidprimary windings to said other side of said potential source, firstbreaker elements for intert 2G riiiit'igisaidhrsteireuittbi'anch andsecond breaker elements for interrupting'lsaid second circuit branch;means for separating said first 4breaker elementsj whilesimultarieoiislyI closing'fsaidlsecond breakerelements and forsepar'atiri'igl's'aid*second breaker elements whilesimultaneoilslyfclosinglsaid first breaker elements, a third circuitbranchlinterconneting the other sides of said primarywindingsgithird':breaker elements disposed in said third circuit branch,means for alternately separating and clos- A ingsaid-` thirdbreak'erelement while said first breaker elements 'are' closed andwhile saidsecond breaker elements are closedi'a pair'f secondary coil windings, aseparate one of said 'secondary windings being electrically coupled toeach of said primary windings, a pair of capacitors, one side of each4oliv-said capacitors being connected to ground, each of the 'other sidesofsaid-capacitors being connected to a separate' one of ysaid secondarywindings, a combustion ignitor means',ja:fourth and' a fifth circuitbranch respectively connetingeachff-said othersides of said capacitorstosaid igniter means, and a spark gap means interposed in each of `saidfourth and fifth circuit branches.

`25. The combination as set forth in claim 24 wherein said sparkgapnieans'includes a pair of main electrodes defining a main spark gapand a pair of teaser electrodes in yclose proxirnityv` to said mainelectrode forming a teaser spark 'lgapf References Cited in the le ofthis patent UNITED STATES PATENTS v2,197,114 Rabezzana et al. Apr. 16,1940 2,447,377 l Tognola et al. Aug. 17, 1948 2,515,370 Hooven July 18,1950 U. S. DEPARTMENT OF COMMERCE PATENT OFFICE CERTIFICATE OFCGRRECTION Patent No., 819,428 January f75 1958 Omer E0 Bowlue et ala Itis hereby certified that error appears in the printed specification ofthe above numbered patent requiring correction and that the said LetterePatent should read as corrected below.

Column 8, linev 35, for "electrons" read me electrodes en; column 9yline 58, for "parteularly" read particularly m; line 65, for "coke" readchoke column l0, line 16y after "so" insert as im; column 13, line l0,for "an" read a me.,

Signed and sealed this 15th day of April 1958o (SEAL) Attest:

KARL Hf MINE ROBERT c. wATsoN Attestlng Officer Comnssioner of Patents

